1. Field of the Invention
The present invention relates to image processing devices, and, in particular, to an image processing device having a gain-coefficient acquiring device for adjusting the brightness of the captured image.
2. Description of Related Art
Conventionally, a solid-state image sensor, such as a CCD image sensor, or a CMOS image sensor, includes an effective pixel area and an optical black area surrounding the effective pixel area. When the image of an object picked up by the image sensor is to be reproduced from image data representative of the image, a black level is corrected by use of data output from the optical black area. However, in making correction, a plurality of optical black areas must be arranged above and below the effective pixel area in the imaging plane. Consequently, it is difficult to further enhance image quality in a high-sensitivity pickup mode, a long-exposure pickup-mode or other similar image pickup modes.
It is desired to provide an image processing device having a gain-coefficient acquiring device, which can overcome the above-described deficiency.